Home Canning Series: V
Pressure Cooker Method
For generations, canning has been a way of preserving the abundance of food from the garden. Today, canning has made a huge comeback as more people wish to have greater control over their family's food sources. If you are new to home canning, don't be intimidated by thoughts of using a pressure canner. When used properly, pressure canners are very safe. At Southern States, we want to take the mystery out of pressure canning and provide you with answers to your pressure canning questions.
Preparation is the key to any successful canning experience.The USDA recommends that a canner be large enough to hold a minimum of four quart-sized jars. Any pressure cooker smaller than that, while great for preparing foods, is not considered safe for processing food for storage purposes. You can choose from either a dial gauge or a weighted gauge pressure canner. While both perform the same task, they differ in how they measure pressure. The dial gauge allows you to see the pressure and monitor any changes, while the weighted gauge is set to certain pounds of pressure. The weights are designed to lift and release any extra pressure during the canning process. If you own an older pressure gauge canner, have it tested annually for accuracy. Your canning jars should be free from defects. Small chips or nicks in the glass can cause breakage during the heating process or prevent jars from sealing properly.
For safety, certain foods must be preserved in a pressure canner based on their acidity level. According to a publication by the Virginia Cooperative Extension, the acidity is determined by the pH level - low-acid foods have a pH higher than 4.6 and high-acid foods have a pH lower than 4.6. Low-acid foods must be processed in a pressure canner in order to destroy any bacteria that could cause botulism. As a general rule, meats and vegetables are low-acid foods and fruits are considered high-acid foods. Examples of low-acid foods include: beans, beets, corn, peas, potatoes, winter squash, meats, seafood and poultry.
While many foods can be preserved, most people are interested in canning vegetables from their garden. For best results, vegetables should always be canned the same day as picking, because the quality and flavor immediately starts to diminish. Choose young, fresh vegetables and avoid overripe and blemished ones because bacteria will grow faster on bruised vegetables. Wash and prep your garden vegetables for canning.
It's always important to follow your owner's manual for step-by-step instructions on how to use your pressure canner. Proper temperature and processing time ensures that any bacteria that might be present are destroyed. For greater detail on the actual canning process, refer to Southern States' Home Canning Series: Canning Methods.